/* 
 * Copyright 2006-2015 www.anyline.org
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 *
 *          AnyLine以及一切衍生库 不得用于任何与网游相关的系统
 */
package org.anyline.plugin.springmvc;

import java.io.IOException;
import java.io.InputStreamReader;
import java.io.OutputStreamWriter;
import java.io.UnsupportedEncodingException;
import java.nio.charset.Charset;
import java.util.ArrayList;
import java.util.List;

import org.anyline.util.ConfigTable;
import org.springframework.http.HttpInputMessage;
import org.springframework.http.HttpOutputMessage;
import org.springframework.http.MediaType;
import org.springframework.http.converter.AbstractHttpMessageConverter;
import org.springframework.util.FileCopyUtils;
  
public class HttpCharsetConvert extends AbstractHttpMessageConverter<String> {  
  
    public static final Charset DEFAULT_CHARSET = Charset.forName(ConfigTable.getString("HTTP_ENCODEING","UTF-8"));  
  
    private final List<Charset> availableCharsets;  
  
    private boolean writeAcceptCharset = true;  
  
    public HttpCharsetConvert() {  
        super(new MediaType("text", "plain", DEFAULT_CHARSET), MediaType.ALL);  
        this.availableCharsets = new ArrayList<Charset>(Charset.availableCharsets().values());  
    }  
  
    /** 
     * Indicates whether the {@code Accept-Charset} should be written to any outgoing request. 
     * <p>Default is {@code true}. 
     */  
    public void setWriteAcceptCharset(boolean writeAcceptCharset) {  
        this.writeAcceptCharset = writeAcceptCharset;  
    }  
  
    @Override  
    public boolean supports(Class<?> clazz) {  
        return String.class.equals(clazz);  
    }  
  
    @Override  
    protected String readInternal(Class clazz, HttpInputMessage inputMessage) throws IOException {  
        Charset charset = getContentTypeCharset(inputMessage.getHeaders().getContentType());  
        return FileCopyUtils.copyToString(new InputStreamReader(inputMessage.getBody(), charset));  
    }  
  
    @Override  
    protected Long getContentLength(String s, MediaType contentType) {  
        Charset charset = getContentTypeCharset(contentType);  
        try {  
            return (long) s.getBytes(charset.name()).length;  
        }  
        catch (UnsupportedEncodingException ex) {  
            // should not occur  
            throw new InternalError(ex.getMessage());  
        }  
    }  
  
    @Override  
    protected void writeInternal(String s, HttpOutputMessage outputMessage) throws IOException {  
        if (writeAcceptCharset) {  
            outputMessage.getHeaders().setAcceptCharset(getAcceptedCharsets());  
        }  
        Charset charset = getContentTypeCharset(outputMessage.getHeaders().getContentType());  
        FileCopyUtils.copy(s, new OutputStreamWriter(outputMessage.getBody(), charset));  
    }  
  
    /** 
     * Return the list of supported {@link Charset}. 
     * 
     * <p>By default, returns {@link Charset#availableCharsets()}. Can be overridden in subclasses. 
     * 
     * @return the list of accepted charsets 
     */  
    protected List<Charset> getAcceptedCharsets() {  
        return this.availableCharsets;  
    }  
  
    private Charset getContentTypeCharset(MediaType contentType) {  
        if (contentType != null && contentType.getCharSet() != null) {  
            return contentType.getCharSet();  
        }  
        else {  
            return DEFAULT_CHARSET;  
        }  
    }  
  
}  